The following abbreviations are herewith defined, at least some of which are referred to within the following description.
3GPP Third Generation Partnership Project
ACK Positive-Acknowledgment
ANDSF Access Network Discovery and Selection Function
AP Access Point
APN Access Point Name
AS Access Stratum
BLER Block Error Ratio
BPSK Binary Phase Shift Keying
CAZAC Constant Amplitude Zero Auto Correction
CCA Clear Channel Assessment
CCE Control Channel Element
CP Cyclic Prefix
CQI Channel Quality Information
CSI Channel State Information
CSS Common Search Space
DCI Downlink Control Information
DL Downlink
eNB Evolved Node B
EPDCCH Enhanced Physical Downlink Control Channel
E-RAB E-UTRAN Radio Access Bearer
ETSI European Telecommunications Standards Institute
E-UTRAN Evolved Universal Terrestrial Radio Access Network
FBE Frame Based Equipment
FDD Frequency Division Duplex
FDMA Frequency Division Multiple Access
FEC Forward Error Correction
GPRS General Packet Radio Service
GTP GPRS Tunneling Protocol
HARQ Hybrid Automatic Repeat Request
H-PLMN Home Public Land Mobile Network
IP Internet Protocol
ISRP Inter-System Routing Policy
LAA Licensed Assisted Access
LBE Load Based Equipment
LBT Listen-Before-Talk
LTE Long Term Evolution
MCL Minimum Coupling Loss
MCS Modulation and Coding Scheme
MME Mobility Management Entity
MU-MIMO Multi-User, Multiple-Input, Multiple-Output
NACK or NAK Negative-Acknowledgment
NAS Non-Access Stratum
NBIFOM Network-Based IP Flow Mobility
OFDM Orthogonal Frequency Division Multiplexing
PCell Primary Cell
PBCH Physical Broadcast Channel
PCO Protocol Configuration Options
PCRF Policy and Charging Rules Function
PDCCH Physical Downlink Control Channel
PDCP Packet Data Convergence Protocol
PDN Packet Data Network
PDSCH Physical Downlink Shared Channel
PDU Protocol Data Unit
PGW Packet Data Network Gateway
PHICH Physical Hybrid ARQ Indicator Channel
PLMN Public Land Mobile Network
PRACH Physical Random Access Channel
PRB Physical Resource Block
PUCCH Physical Uplink Control Channel
PUSCH Physical Uplink Shared Channel
QoS Quality of Service
QPSK Quadrature Phase Shift Keying
RAB Radio Access Bearer
RAN Radio Access Network
RAR Random Access Response
RRC Radio Resource Control
RX Receive
SC-FDMA Single Carrier Frequency Division Multiple Access
SCell Secondary Cell
SCH Shared Channel
SGW Serving Gateway
SIB System Information Block
SINR Signal-to-Interference-Plus-Noise Ratio
SR Scheduling Request
TAU Tracking Area Update
TBS Transport Block Size
TCP Transmission Control Protocol
TDD Time-Division Duplex
TDM Time Division Multiplex
TED Tunnel Endpoint Identification (“ID”)
TX Transmit
UCI Uplink Control Information
UE User Entity/Equipment (Mobile Terminal)
UL Uplink
UMTS Universal Mobile Telecommunications System
V-PLMN Visited Public Land Mobile Network
WiMAX Worldwide Interoperability for Microwave Access
WLAN Wireless Local Area Network
In wireless communications networks, various solutions to support interworking with WLAN access networks may be implemented. For example, some solutions may be based on high-level methods that do not use any radio-level interworking. One characteristic of these solutions is that the LTE and WLAN radio elements and procedures are not impacted. As another example, certain solutions may be based on radio-level methods that use radio-level interworking between E-UTRAN and WLAN. In such solutions, an eNB may receive WLAN measurement reports from a UE and decide to hand over traffic from one access to the other, or to aggregate the radio resources on both accesses.
Radio-level solutions may include a solution specified by 3GPP called “LTE-WLAN Radio Level Integration and Interworking Enhancements” [hereinafter “LWA”] and another solution specified by 3GPP called “LTE-WLAN RAN Level Integration Supporting Legacy WLAN” [hereinafter “interworking with IP tunneling”].
In an LWA solution, there is a new interface “Xw” between an eNB and a WLAN termination. As may be appreciated, a WLAN termination may be any WLAN element in a WLAN network, such as an AP, that terminates the Xw interface. The Xw interface may be used for preparing resources in the WLAN before handing over data traffic from LTE. In certain configurations, the eNB receives DL IP packets from an SGW in a core network, encapsulates these packets into PDCP PDUs, then forwards the PDCP PDUs to a UE either over E-UTRAN access, or over WLAN access (via Xw). In other configurations, the eNB may use both E-UTRAN access and WLAN access to forward PDCP PDUs to the UE, in which case the eNB aggregates the radio resources on both accesses.
Radio-level solutions for LTE-WLAN interworking and high-level solutions for LTE-WLAN interworking may not be coordinated. Accordingly, the radio-level solutions and high-level solutions may be applied independently and simultaneously, resulting in traffic routing conflicts. For example, a high-level solution may steer some traffic to LTE access but an underlying radio-level solution may steer the same traffic to WLAN access.
In one traffic conflict steering scenario, a PGW applies a high-level traffic steering solution that steers some IP flows to LTE access and some other IP flows to WLAN access. The steering applied by the PGW may be based on a NBIFOM solution wherein a steering policy (i.e., a set of routing rules) is configured in the PGW. If at the same time, an eNB applies a radio-level traffic steering solution, the eNB may steer some traffic to WLAN access even though such traffic was meant to be sent on LTE access according to PGW's steering policy. Such steering conflicts may be more severe in roaming scenarios in which the PGW resides in a H-PLMN and the eNB resides in a V-PLMN. In such cases, the steering policy of the H-PLMN (enforced by the PGW) should not be overridden by the steering policy of the V-PLMN (enforced by the eNB).
In another traffic conflict steering scenario, a UE applies autonomously (e.g., without any network involvement) traffic steering between LTE access and WLAN access by using ANDSF traffic steering rules that have been either provisioned over the air or have been configured in the UE via other means (e.g., during manufacturing). The UE, based on the active ANDSF traffic steering rules has decided to route an IP flow (e.g., a TCP connection towards a cloud server) via LTE access. Therefore, the UE establishes the TCP connection over the LTE interface and sends UL packets on the LTE interface. The UE also expects to receive DL packets for this TCP connection over the LTE interface. If, however, an eNB applies a radio-level traffic steering solution, some DL packets may be redirected by the eNB to WLAN access. This redirection of traffic to WLAN essentially overrides the traffic steering policy in the UE and should be avoided.